1. Field of the Invention
The present invention relates to a seatbelt system for a vehicle designed to restrain the body of an occupant when an emergency situation of the vehicle occurs. More particularly, the present invention pertains to an automatic seatbelt system for a vehicle which enables a webbing to be automatically fastened to the body of an occupant after seating himself in a seat provided on the vehicle.
2. Description of the Related Art
There are various types of automatic seatbelt system for a vehicle which are adapted to enable a webbing to be automatically fastened to the body of an occupant. As one type of such automatic seatbelt system, a structure has already been proposed wherein a slider is provided in such a manner as to be movable along a guide rail laid on the body of a vehicle, and this slider is activated by drive means so as to move a webbing which is retained at one end thereof by the slider.
The guide rail employed in this system is arranged such that an end portion thereof which is closer to the rear end of the vehicle is terminated after being bent so as to extend downward in the substantially vertical direction along a center pillar, thereby allowing the guide rail to reliably carry the tension generated in the webbing by the inertia which acts on the occupant's body when an emergency situation of the vehicle occurs. The guide rail arranged as described above needs retainer means for retaining the slider in such a manner that the slider is inhibited from moving toward the ceiling of the vehicle along the vertically extended portion of the guide rail when the vehicle overturns.
Seatbelt systems having such retainer means have already been devised wherein a sensor such as a pendulum for detecting overturn of the vehicle is provided, and the movement of the slider is inhibited when this sensor is activated (e.g., Japanese Patent Publication No. 15716/1985). This type of retainer means suffers, however, from the problem that, since a sensor such as a pendulum projects from the guide rail, it is necessary to form a bore in the center pillar for receiving such projecting sensor structure or provide a raised portion on the center pillar which protrudes into the compartment of the vehicle.